Subject: SOHO/LASCO Partial HALO CME 110914

UCMEO 93001 10915 1713/
10914 60000 81054 2181/ 117// 123// 40461
10913 62124 82318 41322 11289 1212/
99999

PLAIN

SOHO/LASCO observed a Partial HALO CME on September 14, 2011.  Event is first
seen in C2 at 00:00 UT as wide loop partially surrounding the occulter over the
north and west.  The front expands PA 218-117 degrees for a total coverage of
259 degrees over the North and West. The event continues into the C3 field
beginning 00:54 to 10:54 UT out to 27 Rsun where it dissipates.

Time/height measurements were marked at 11 points in C2 with speeds of 349.7 Km/sec
at position angle 313 degrees. The event is marked to 12 points in C3 where it
accelerates.  Speeds average through both fields to 461.0 Km/sec at PA 308 degrees.
Acceleration of 9.92 m/sec^s.

SDO/AIA 193 shows a CME beginning in the north area of sigmoidal AR 11289 located
[N22, W03] at 21:24 UT.  An emission from the southern area of the region
at 21:57 UT begins along with a dual ribbon characteristic flare and post loop
arcade between the areas by 02:09 UT.
STEREO COR2 A has a data gap until 9/14 01:54 UT then shows a large loop CME in
progress over the East.

This is most probably the cause of the Partial HALO event seen in LASCO.

   
The observation of this event is considered 'GOOD'. This CME is determined a FRONTSIDED event.

Images and movies and time/height information for this event is available on the web at:

http://umbra.nascom.nasa.gov/lasco/observations/halo/2011/110914/

Best regards,

Kevin Schenk
Solar Heliospheric Observatory
EIT and LASCO Operations
NASA-Goddard Space Flight Center, USA

BT